Improvement in steam-engines



G. T. MAY.

STEAM ENGINE.

No. 41,229, PATENTED JAN. 12, 18645 UNITED STATES PATENT 'A UFFICE.

' GEORGE T. MAY, OF TOMIKINSVILLE, NEW YORK.'

IMPROVEMENT InN STEAM-ENGINES.

Specification forming part of Letters Patent N0.A 41,*2-29, dated January 12, i864; antedaicd DcceinberOJS 33.

.To all whom, it may concern: j

Be it known that I,l GEORGE T. MAY, of Tompkinsville, in the county of Richmond and State of New York, have invented anew and useful Improvement in Steam-Engines; and I do hereby declare that the following is a full,

true, and exact description of the same, referinder of about half the capacity or more or less'of the working cylinder or cylinders of the engine, open to the atmosphere at one endl or above the piston, and kept continuously" charged at'fthe other endor below the piston,

with steam or other confined elastic fluid, the action of the piston-when operated by a conneetion from the working-shaft of the engine having the effect to alternately compress and attenuate th'e'elastie flu-id under it, andthereby to greatly diminish or retard with each descending stroke the development of the en gines power' effectively during one part of a revolution, and tov greatly enhance'with each ascending stroke the development of the enf 'gines power effectively during another part of the revolution, this operation of modulat ing the effectiveness of the developed power of the engine beinglfurther assisted bymeans of areservoir attached tothe cylinder, and, ify steam be fthefforce employed, appropriate steani 'pc'rts'and valves, provision being also made in-'this case for' maintaining a sufficient elastic "force in the' chamber of v the cylinder by passingoii" thec'o'ntents into a working'A-'cyl inder and 'replenishing from the steam-chest,-

at favorable points of the revolution, thus, if

desired, passing all the steam used by the engine yfirst through the modulator, subject to use there or not, as required.

The'object of, the improvement is to Withhold aAneedls's'or injurious expenditure of powendnringthose parts of a 'revolution where the .resisting force is at a minimum,

' whilestill admitting of a Auniform 'developa lInel'it-fofpower through the engine fprop'er, v andwthcnit' exert ubSt-antiallyftli' Whole:

power vso reserved, in addition to the `mean effective power of 'the engine,-fat those points of -the'revolution where the resistingforce-is at a maximum, in cases where 'the variation of resistance at :different points of a revolution is very great'I I denominate the improvement a.steammodulator.

Figure 1 is a front elevation of theimprovement, with Vertical section through cylinder and reservoir. Fig. 2 'is a side view., section vertically through the steam-chest B. Fig. Sis a side elevation of the improvement, with section vertically through thel valve-boxes C and D. Fig, 4 is a plan View, section horizontally Athrough the trunnions, steam-chest,

cylinder, and valveboXes.

'AIhe improvement 1s operated by lgearingor other equivalent means from the'working-shaft of the engine; y It'ishere represented as oscillating to correspond in character with a double oscillating marine engine; but it may be fixed and may be also operated, horizontally,verti cally,` or inclinedly, to suit the. requirements of dierent engines. e

v J is the modulator-shaft. K is the modulator-crank`. O is a cogged Wheel of the gearing. F is the modulator-cylinder open to the atmosphere above the piston by apertures L. Lin the cylinder-head. Mis the'cylinder-- bottom;` H, the piston rod, and I the piston. Gis the reservoir. Steam enters the steamchest of the' modulator from the boiler through the steam-channel in the t'rlunni'on' A. Bis the steam-chest. There are four l l steam-ports, or passages regulated by valves. The'yfare l indicated by figures, (nnmerah) viz.,'1,' 2 and 2,5 3,v and 4. P ort 1 admits steam directly intothe reservoir G from the steam-chest B. Port/3 admits steam. directly into the cylinder-chamber from the steamchest B. -The steam-passage' from .fthe cylinder F into thereservoir Gisbythe ports 2 and 2 through the valve-box C, the whole forming one passage. Port 4 is the place of exit from the reservoir through the valve-'box D into thesteam-`L channel of vtrunnion E, whence thesteam, having done its ,work in the modulator,` may pass tothe working-.'cylindersof the engine;; or,'i desired', the sjteamapipe itself may pass aroun or. through v the-{reservoir in any. convenien'` a ufzae way, when the two steam-channels of the trunnions A and E would in e'r'fect constitute a part ofthe ordinary steam-pipe from boiler to engine into which the modulator isinterposed. rPhe steam-pipe, not. being claimedin this improvement, is not shown in the drawings.

The Inode of operating the improvement is as follows: The piston being at half-stroke, the three steam-ports l, 2 and 2,', and Bopcn, and the port 4 closed, the pressure upon the piston will ber-approximately the same per inch as lthe pressure in the boiler, the communication being free. Let the ports 2(2 remains pei" manently closed) and 3 be closed and the piston ascend. At the end of the ascending stroke the pressure upon' the piston is reduced by expansion of the steam to about one-half of what it Was at the half-stroke. The enhancing effect ofthe modulator upon the engines work is now at a minimum. As soon as vthe upper deadpoint is Well passed, let thev ports 2 and 3 be opened again, and the port 4 be now also opened. At the halfA stroke in deseending,the pressure lin the cylinderwill again be about equal with the boiler pressure, or rather greater; butnow it will be against the piston, and detractivefrom the engines eiective Work By openinglthe port 4C, yport l having previously been and remaining open,steam has flowed. freely through the reservoir and from ythemodulatorby the steam-channel in trunnion Eto theworkng-cylinders; and now,port 4 being closed atthe'half-stroke, the reservoir is filled substantially with fresh steam from the boiler. Let ports 1 and 3 be now also closed,

port 2 remaining open. As the pistonde'seends,

the steam below itis driven from'the cylinderchamber`and compressed into the reservoir beneath.' At the end'of the descending stroke" thedetraction fromv the engineseiect is at its maximum. Ou the lower dead-point close the port 2, and asthe piston againcommences as cent open the port 2. (In practice this opening should be so gradually effected thatthe equilibration of steam-pressure should occur i at about one-fourth `of thc pistonsfasc'ent.)

The enhancing effectof the modulator is then at about one-fourth of theascent, at a maX`i-' mum. 'Open now ltheports 'l and 3,andjatv the y half-stroke of the ascentth'e steam-pressure on the piston will be again about equal with the pressure in the boiler, and allthe ports will be restored to the condition from which the start was made.

Eccentrics on thelimodulator-shaftmay be arranged toreadily effect the necessary motion. vof valvesad-apted tothe ports; and each'revo- ,lutionfof the modulator-shaft will then cause a repetition of the above described process.

The ratio of revolutions of the modulatorshaft to one of the working-shafts may be varied as necessary to meet the requirements of particular' cases. If one mo'dulative process 'only is required in a revolution, the modulator piston-rod may be cranked directly to the work-ingfshaft. y n

".lhey arrangement of theports and waives may also be modified to vary the operative effect of the modulator as may be necessary for the various purposesto which it may be ap' plied.

If desired in any particular case, the reservoir may be dispensed with and two ports be only used, one to admitand the other to emit steam.

In practice the ports should be as large and the valveboxes small as they can consistently be maden f' The cylinder above the piston being open to the atmosphere,the cylinder-head and stnngbox are to be constructed, mainly, with a view to serving as a guide and support for the pistonrod.

The advantages thatv I claim for this improvement are that for purposes where the object is better attainable by an intermittent exertion of greater force than by aconstant exertion of less force the motive power maybe more eiectively' exerted, and that the great waste of power 'and theviolent shocks and jars that would result from the use'of ordinary engines as thyfar'e' for such purposes may also be by the employmentl of this improvement greatly modified. jj ,f' p

The valves, with their valve-rodsl? P P" Pf andthe -ecceutrics Nj N N N, are not claimed by meas composing-7a part of this described' invention.,A Any:A kind of valve andyalvelll-i tion maybe used to suit the views oft-hetens tructor. Neither do I claim, formally,"fo'rtlrea exactA disposition of the parts, of the'finyexrtiiil as described, provided they be` substantie-uy so, because in'praetice it will be necessary 'to conform to very'dierent conditions in variousA cases.- Nor do I claim at all for any component part of any kind of steam or air engine as now known or used. 'Nor do I claim any part or parts of the machine described in Letters Pat- .ent issued to J. F. Winslow, January 14, 1862,

wherein the device and' process dbiier from mine-first, in that ,the pressure'of ste'am in the boiler or steam chestr is theresubstan- Itiall'y the steam-pressure on the piston during its operation; and, secondly, in that the said device is not designed toexert reaction in any wayto modulate the engine, 'but is clearl'yintended to expendall the power exerted upon its piston inl producingamechancal result, as

'a ram ,or hammer, at otherand foreign points,

altogether'diiierent from the purposeof my device, whichzis' for alternately compressing a 4volu'meof steam` cut oli' from tlieboiler-presslure into aspace very much smaller than that due to itfrom the boiler-pressure, and attenyuating the same to' aybulk very much'greater than conid'be 'obtained' if the boiler-pressure Werenot cutoff from the' piston for that 'purpose, the Whole e'ect of the process in the steam-modulator resulting in modulative reaction, plus and minus',vupon the engine.

What I do claim" as my invention, and desire to secure by Letters Patent, isy l. -The reservoir G, yin connection "with a rnoiulator-cylinder, F, substantially as speci- ,anne 3 J2. The eombina'tioiof a modulatorcylinder,

siantially as and for the purpose set forth.

4. The art or method of modulating the mechanical e'ect throughout the revolution of `an engine by means of the reaction obtained from a volume of steam or other elastic uid,

out o'ilt' at the appropriate moments of time from the boiler-pressure, (if steam, or equiva- 1ent,if other Huid/Q and submitted to the proeessof alternate compression and attenuation t undex1 apiston operated from the engine,'said process of compression and attenuation being eeeted Within a combined modulator cylinder and reservoir, substantially as described.

GEORGE T. MAY.

Witnesses: v

A. COUPER, J om: PRATT. 

